trailmug Posted June 9, 2021 Share Posted June 9, 2021 What's the tstat set to? I suppose on the wilder end of the spectrum, the dish box could be injecting RF noise onto the sensor wire. Link to comment Share on other sites More sharing options...
Steven P Posted June 9, 2021 Author Share Posted June 9, 2021 Typically I keep it is set to 74 or 73. But after moving it, I had to drop to 72 for more comfort. The morning sun is hitting the wall not far from the sensor and there is a 5 deg difference bw that wall and where the sensor is. Link to comment Share on other sites More sharing options...
Larry Laursen Posted June 10, 2021 Share Posted June 10, 2021 On 6/8/2021 at 6:43 AM, Steven P said: Just a quick update. Last night I pulled the 2 remote sensors (why are there 2? What do both do?) Further out of the cabinet and noted more short cycling. So, when I went to bed I pushed them further in and noted no short cycling. It's too early to tell if this will be the solution or not, but there's hope. See pic. @Scotty Hutto The second sensor is for the auto gen start. It runs from the bedroom temp. 1 Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted June 10, 2021 Share Posted June 10, 2021 RV a/c temp control at best is a hit & miss dance. It seems every day is different. I have gotten up at night and set the temp down so low it would not cycle at all. I like to have it cold and pull up the covers anyway. In some humid & warm locations the cycling will lead to getting warm, kicking the cover off only to pull the covers back up later. I end up cycling the covers when the air cond cycles the temp, that's not a recipe for a good nights sleep. Installing too large of an air cond in a home can cause similar problems where the air feels cold but clammy / damp. A/C needs to run long enough to remove the humidity to a comfortable level Link to comment Share on other sites More sharing options...
jacwjames Posted June 10, 2021 Share Posted June 10, 2021 7 minutes ago, Ray Davis said: Installing too large of an air cond in a home can cause similar problems where the air feels cold but clammy / damp. A/C needs to run long enough to remove the humidity to a comfortable level Our home AC unit is sized properly. A while back I couldn't figure out why it continued to run while the thermostat was set at 73F and the temp was colder then that. I started checking and my very DW over road the temp setting and initiated humidity control down to 50%, which in TN I doubt it could ever get to. I had a long talk with her on how futile this was. My next step will be to install a lockable guard over the top of it 😝 1 Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted June 10, 2021 Share Posted June 10, 2021 3 minutes ago, jacwjames said: My next step will be to install a lockable guard over the top of it 😝 You might want to round up all of the rolling pins too. Do people still have rolling pins? I'm not sure I've seen one around here in a long time. I remember my mom using one making pie crusts, fond memories for sure. Link to comment Share on other sites More sharing options...
Chuck B 2004 Windsor Posted June 10, 2021 Share Posted June 10, 2021 Wives have ways around that. Us husbands end up loosing that battle. Chuck B 2004 Windsor 1 Link to comment Share on other sites More sharing options...
Steven P Posted June 11, 2021 Author Share Posted June 11, 2021 (edited) Ok. It's been a couple of days so time will tell more, but so far so good. The PO had cut a hole in the side of the wardrobe for speakers. Currently my sensor is coming out of that hole, but is behind the art I placed to cover the hole and no more short cycling. It runs as I feel it should. I did have to lower the tstat to 72 to keep it how I like it. I'm gonna leave it here a while and see how it goes. Outside Temps have reached 90 w high humidity, but I haven't been in the coach much in the day (working). Edited June 11, 2021 by Steven P Added pic Link to comment Share on other sites More sharing options...
Steven P Posted June 16, 2021 Author Share Posted June 16, 2021 Just an update. So far so good. Since the remote sensor move, I have had only 2 known short cycle times vs tons! I'm gonna leave it here for a bit and see how it continues to go. Link to comment Share on other sites More sharing options...
Ivylog Posted June 16, 2021 Share Posted June 16, 2021 I can’t take credit for messing with the temp sensor helping this problem. Several years ago I sent a PM to Doug Rainer on RV.net… he is a longtime RV tech in TX and willing gives excellent advice. 1 Link to comment Share on other sites More sharing options...
Steven P Posted June 30, 2021 Author Share Posted June 30, 2021 I thought I'd give an update. After 2 to 3 weeks of the AC doing well, it started short cycling again. I realized that w the front AC set several degrees higher than the bedroom, the rear would cycle more often and sometimes short cycle. When I lowered the front room temp, the rear did better. When it started short cycling, I had installed the little sensor cover under the picture just for comparison and that made changes even though the sensor's position was relatively the same. I did a hard reset on the thermostat w no change. Now I have the pic down again and the sensor moved and will see how it goes. That sensor seems to be very sensitive. Link to comment Share on other sites More sharing options...
Steven P Posted August 28, 2021 Author Share Posted August 28, 2021 Just another update if anyone wants to know the outcome. I found a new place that has done the best. Kind of in the corner under the TV cabinet about a foot from the original location. I've just left the sensor resting there but am thinking of a permanent move there. Also, my front sensor is on an outside wall which is not recommended per the AC installation instructions and I found the sensor was turned back in going into the wall. I reversed that and showed a paper towel into the hole and it keeps the Temps better. However, that wall will easily read low 80s on a normal day so I turn that thermostat to about 81 in the day. Keeps the room about 74. Link to comment Share on other sites More sharing options...
Scotty Hutto Posted August 13, 2023 Share Posted August 13, 2023 Reviving this old thread… Noticed this behavior from my front AC while camping (glamping?) this week. Read through the thread (again), and have a few comments… I agree with Dick @Ivylog that the short cycling is caused by the remote thermostat. When I checked mine, connections at the control box (in the return air plenum, accessible from inside the coach) were good. Cleaned them again for good measure. I decided to check my remote t-stat placement, and found that somehow in the last two years, the actual bulb of the t-stat had been shoved back into the wall, almost touching the exterior skin of the coach!I rectified that and the short cycling has stopped altogether. I will note that as one who in a previous life used to design HVAC units and later on, systems, short cycling does reduce the lifespan of the unit. So I’m not surprised to hear of folks having to replace dead units after they were short cycling. In the end, I do think Steven @Steven P replaced both units as a preventative/predictive measure. If I had been smart and listened to my friend, I would have done so too. Back when they could be had for about $1,100/unit. 🤦🏻♂️ They are literally twice that (or more) now. Guess I’ll just keep these 16-year-old units running as long as I can. They still cool (and heat) very well. FWIW… it’s not uncommon for heat pumps to run 25+ years in the southeast, with the average being just north of 22 years, according to a study I was involved in back in the 1990s. The hypothesis at the time was that they lasted longer than straight AC units because they were used year-round and didn’t sit unused through the winter. The same study showed the average life of a straight AC unit was closer to 16 years. (Sample size for the study was approximately 10,000 homes in MS, AL, GA, & FL) so, just like so many things in life, the old adage applies… “Use it or lose it!” 1 Link to comment Share on other sites More sharing options...
Steven P Posted August 13, 2023 Author Share Posted August 13, 2023 @Scotty Hutto you're right, I did replace both of them. We haven't been able to use the coach as much, but the new units do keep it cooler and then the compressors kick on and off it's so much quieter and without that shudder. Link to comment Share on other sites More sharing options...
Tom Cherry Posted August 13, 2023 Share Posted August 13, 2023 Our sage and esteemed owner, VIPER, perhaps you know of him….LOL….wrote a long post way back in 2009 or so as he was still doing the “shakedown” on his former 2005 Executive. The sensor for his rear had “retracted” and was giving him fits. He pulled the cover and then extended it to just barely be not touching the inner surface of the cover after he reinstalled the cover. I THINK he put a dot of hot melt or maybe a zip tie or some “fix” to keep it from wiggling loose and retracting. Seemed like a good plsn and mine is wedged in place and protruding. The impact of a front unit or a middle unit will (can) have an impact on the rear as there is one long continuous duct on one side and probably (maybe) a truncated duct (not connected due to shower placement on the other side. Some folks have tried to actually heat a zone and then super cool another. Dometic will not allow that. But setting more than a 2 - 3 Delta T temperature differential is a NO NO per Dometic….and this came from s knowledgeable Dometic tech support guy who spent time on the phone with me and let me give him motor and compressor temps when i thought i had s problem. He knew exactly how the Monaco’s were installed and ducted. Bottom line, my rear always runs lower…DUH…smaller volume and area. I leave all the duct or vents OPEN and throttle down the potty, a bit. I aim them so that they don’t hit the bed and we get frostbit….but not at the remote sensor. One has to understand and experiment. Some models were a perfect (blind swine….acorn phenomena) while others were not as good… Link to comment Share on other sites More sharing options...
96 EVO Posted August 14, 2023 Share Posted August 14, 2023 12 hours ago, Tom Cherry said: But setting more than a 2 - 3 Delta T temperature differential is a NO NO per Dometic…. HA.... Not a rule I ever have, or will, follow! I'll bet you won't see them putting that in writing 😀! 1 Link to comment Share on other sites More sharing options...
Tom Cherry Posted August 14, 2023 Share Posted August 14, 2023 1 minute ago, 96 EVO said: HA.... Not a rule I ever have, or will, follow! I'll bet you won't see them putting that in writing 😀! Suit yourself. I only report what tech support tells me…and, after at least 25 calls to Magnum over the years for me and a faulty remote…and how to troubleshoot and at least half or 15 or so within the past few years to get info to help others….YEP. The tech’s tips or “do it this way” are never written down, but we have 3 or more members that tried everything….and finally, increased the time period from whatever was in the write up to 30 - 40 minutes to let the stored gremlins dissipate. All of them never had to replace the inverters and are happy today. Yep…. Sometimes you learn when you listen. I’ve never had the dreaded short cycling…and the Dometic techs said that was NOT GOOD for the units. My HVAC has been on for at lest 3 years, in total, due to our 60 nights out plus 3 or 4 days prior to and after every trip. We, the staff, try to clarify or give information that is factual and correct so that some of the myths that folks post, like “Keep the exhaust brake on and never turn it off” or “wedge a golf tee under the boost switch and you will keep the batteries charged without a fancy system”. Now to clarify…if one has some of the older “NON BIG BOY boost solenoids that are rated for full 12 VDC, then that would work…but folks often say that and include the word Big Boy. That’s our motto…suit yourself and if it works, then fine, but some folks take every post with such advice as gospel…. We rarely edit or clarify…but try to prevent premature failure or damage… we will as needed. Mine work fine and I need the 3 degree higher set point in the rear to keep the entire MH uniform. Your milage my vary Link to comment Share on other sites More sharing options...
96 EVO Posted August 14, 2023 Share Posted August 14, 2023 Yeah, imagine a family pulling their TT all day in 100F heat, and when they finally get set up in their site, telling them they should set the thermostat to 97. Not gonna happen! Link to comment Share on other sites More sharing options...
Scotty Hutto Posted August 14, 2023 Share Posted August 14, 2023 1 hour ago, 96 EVO said: HA.... Not a rule I ever have, or will, follow! I'll bet you won't see them putting that in writing 😀! I think Tom means a 3° delta T between the front and rear AC units. Not 3° from the outside temp. 😉 If both units are running (or all three if you are so lucky), their thermostats should be set within 3° of each other. 1 1 Link to comment Share on other sites More sharing options...
96 EVO Posted August 14, 2023 Share Posted August 14, 2023 Ahhhhhhh! Thought he meant 3deg lower than room temp 😀! Link to comment Share on other sites More sharing options...
VinceB Posted August 14, 2023 Share Posted August 14, 2023 In high humidity areas both my AC's will short cycle. I figured out that the evaporator coils were icing up - we like to run pretty cold. So I set the fans to run continuously on high and problem solved. Link to comment Share on other sites More sharing options...
96 EVO Posted August 14, 2023 Share Posted August 14, 2023 2 minutes ago, VinceB said: In high humidity areas both my AC's will short cycle. I figured out that the evaporator coils were icing up - we like to run pretty cold. So I set the fans to run continuously on high and problem solved. Yeah, I always set the fan's to high speed! The few times I've used 'Auto', I find the fan switches to low speed much sooner than I would like! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now